The long-term goal of this research project is to examine the functional importance of putative neurotransmitters (dopamine, norepinephrine, 5-hydroxytryptamine) in the central nervous system. The immediate objective is to utilize a cerebroventricular perfusing technique in cats to detect the release to these transmitters from nerve terminals in the brain following appropriate electrical stimulation of various brain regions and the administration of drugs. Bibliographic references: Moore, K.E. and Thornburg, J.E.: Drug- induced dopaminergic supersensitivity. In.: Dopaminergic Mechanisms (ed. D.B. Calne, T.N. Chase and A. Barbeau). Advances in Neurology 4: 93-104,1975; Chiueh, C.C. and Moore, K.E.: d-Amphetamine-induced release of "newly synthesized" and "stored" dopamine from the caudate nucleus in vivo. J. Pharmacol. Exp. Ther. 192: 642-653, 1975.